The present invention relates to a method and a machine for filling and sealing receptacles such as flexible tubes or rigid reservoirs equipped with fluid dispensers. The machine defined by the invention is thus applicable to the field of packaging fluids in general, and more particularly cosmetics or pharmaceuticals such as creams, lotions, or even more-watery liquids.
The industrial sectors of pharmaceuticals and of cosmetics, among others, produce many delicate fluids that require very good quality packaging. Certain fluids are sensitive or even reactive to air, to light, to humidity, etc. It is therefore necessary for the packaging of such fluids to protect them from such damaging environments.
A technique that is in wide use for fluids that are not too sensitive consists in providing the reservoir containing said fluid with an xe2x80x9cairlessxe2x80x9d dispenser device, i.e. a dispenser device that has no air intake: as the fluid is dispensed, the volume of the reservoir decreases correspondingly so that the fluid is never in contact with air inside the reservoir. That type of dispenser device is in common use for fluids that tend to oxidize.
In the field of vacuum packaging, mention may be made of Document GB 246 347 which describes vacuum canning apparatus. That apparatus is provided with an inlet via which non-sealed filled cans are inserted. The cans follow a circular path on a rotary carrousel. Over a portion of the rotary path, the cans are subjected to a gradually increasing vacuum. The manner in which the vacuum sealed cans are removed from the carrousel to bring them back to ambient pressure is not described. The object of that apparatus is to seal cans under a vacuum without any sudden variation in pressure, which would disturb the contents of the still-open cans and thus cause said contents to be spilled. The problem of packaging delicate fluids is not addressed since the cans are filled at ambient pressure outside the apparatus.
Mention may also be made of Document U.S. Pat. No. 5,481,851 which describes apparatus for canning waste. In that apparatus, empty cans are inserted into a rotary carrousel via an inlet. The cans pass through various stations in which they are purged with nitrogen, they are filled with waste, they have their air evacuated from them, they are sealed, and then they are unloaded from the apparatus. Clearly, the cans are sealed in ambient air at the outlet door. The purpose of evacuating the air is not to achieve vacuum sealing, but rather merely to extract the air from the can.
For more sensitive fluids that are difficult to preserve, use is made of vacuum packaging techniques. The reservoir is sealed in an enclosure in which a certain degree of vacuum prevails. This guarantees that the fluid is not packaged in the reservoir together with air, which could damage it.
Document U.S. Pat. No. 3,006,120 describes apparatus for evacuating air from pouches, and for then filling them with gas and sealing them. Each pouch is brought into a rotary carrousel provided with sixteen enclosures, each of which serves to receive a respective pouch. Each enclosure comprises a cup and a lid to which an air evacuation line and a gas filling line are connected. Each lid is also provided with a sealing jaw system. There are therefore as many lines and as many sealing systems as there are enclosures, i.e. sixteen air evacuation lines, sixteen gas filling lines, and sixteen sealing systems. It is further necessary to break the vacuum in each enclosure for the purposes of removing the filled and sealed pouch, and of inserting a new pouch. That takes time. It should also be noted that the fluid packaged in the pouches, i.e. the gas, is not a delicate fluid, and the only object of removing the air is to improve the filling with gas, and not to keep the gas from the air. The filling gas occupies the entire volume of the enclosure so that there is definitely only gas in the pouch when it is sealed. That does not apply with liquids.
For very sensitive fluids, it is also necessary to incorporate preservatives in the fluid in order to improve stability because the fluid may be in contact with air before it is packaged. Adding preservatives has an impact on the cost of the fluid, and can, for some fluids, cause allergic reactions in the user.
An object of the present invention is to remedy the drawbacks of the prior art by defining a machine for packaging sensitive liquids that makes it possible to reduce, or even omit, preservatives. In addition, the machine should be capable of operating at high throughput. It should also be as compact as possible.
To this end, the present invention provides a packaging machine for filling and sealing receptacles, said machine having a plurality of stations at which packaging operations are performed by packaging means, the stations comprising at least a filling station and a sealing station, said machine including conveyor means for causing the receptacles to travel along a path passing through the various stations, the stations being disposed in an enclosure in which a vacuum prevails. By making provision for the filling and the sealing to be effected in a single common enclosure in which a vacuum prevails, it is possible to guarantee that the fluid to be packaged is never in contact with the air, so that it cannot be degraded. The fact that the fluid to be packaged is worked in a continuous vacuum makes it possible to reduce the quantity of preservatives required for its stability. Not only is the fluid less costly because of the small quantity of added preservatives, but also the fluid is purer. Another visible advantage procured by the invention lies in the fact that the throughput of the machine may be accelerated, since there is no longer any interruption of the vacuum during the filling and sealing step.
In addition, since the stations are placed in a common enclosure, all of the stations are common to all of the receptacles because they travel from one station to another. This does not apply in the device of Document U.S. Pat No. 3,006,120 in which each receptacle is placed in an individual enclosure equipped with packaging stations. Once the receptacle has been filled and sealed, the enclosure is opened. This does not apply in the invention, with a single enclosure housing all of the stations. The enclosure does not need to be opened under normal operating conditions.
According to technical characteristics of the invention, the conveyor means are in the form of a rotary carrousel equipped with a plurality of receptacle-receiving means for receiving the receptacles. The path described by the conveyor means thus forms a loop. In addition, the enclosure includes a vacuum bell which covers said plurality of stations in airtight manner. Advantageously, the packaging means are secured to the vacuum bell. In addition, the bell is provided with an insertion airlock for inserting empty receptacles, and with an ejection airlock for ejecting filled and sealed receptacles.
In one embodiment, the packaging means include hot air sealing means serving to seal flexible receptacles. This technique of sealing by heating with air is a known technique in packaging fluids in flexible casings or tubes. However, a paradoxical characteristic of the present invention lies in the fact that such a technique is used in a vacuum enclosure. Whereas other known techniques such as sealing by ultrasound, induction, or heater jaws are more easily imaginable in an enclosure in which a vacuum prevails, because they do not use air, the technique used in the invention goes against the requirements of vacuum sealing because hot air is forced into the enclosure, which would normally break or weaken the vacuum.
The technique of heating by air is advantageous compared with the above-mentioned techniques because the mechanism is simpler and makes it possible to heat only the inside wall of the flexible receptacle. In addition, it makes it possible to obtain higher throughputs. With heater jaws, it is necessary to have three of four pairs of jaws to obtain the same throughput.
Alternatively or additionally, the packaging means include crimping means for crimping a dispenser device to the neck of a reservoir. Also alternatively or additionally, the packaging means include snap-fastening means for snap-fastening a dispenser device to the neck of a receptacle. Advantageously, the vacuum bell is provided with an insertion airlock for inserting dispenser devices. The machine of the invention may comprise a plurality of stations specifically adapted to packaging a plurality of different types of receptacle. To this end, the receptacle-receiving means may be modulated or interchanged as a function of the type of receptacle to be received.
The invention is described more fully below with reference to the accompanying drawing which gives an embodiment of the invention by way of non-limiting example.